Supreme Court Justice Clarence Thomas’ decadeslong friendship with real estate tycoon Harlan Crow and Samuel Alito’s luxury travel with billionaire Paul Singer have raised questions about influence and ethics at the nation's highest court.

Influential Democratic lawmakers have called for immediate investigations and vowed to create stricter ethics rules following a ProPublica report that revealed Justice Clarence Thomas has, for decades, failed to disclose luxury trips he received from a real estate magnate and conservative megadonor.

Illinois Sen. Dick Durbin, who chairs the Senate Judiciary Committee — influential for its role in vetting and confirming Supreme Court nominees — said his panel is calling for an “enforceable code of conduct” for justices. “The ProPublica report is a call to action, and the Senate Judiciary Committee will act,” Durbin said.

Lawmakers and advocates have long called for codified ethics rules that prohibit the type of behavior uncovered by ProPublica’s investigation.

For more than two decades, records and interviews show, Thomas has accepted luxury trips virtually every year from Dallas billionaire Harlan Crow without disclosing them. Thomas has vacationed on Crow’s superyacht around the globe, flown on Crow’s jet and typically spends about a week every summer at Crow’s private resort in the Adirondacks, the investigation found.

These trips appeared nowhere on Thomas’ financial disclosures. His failure to report the flights appears to violate a law passed after Watergate that requires justices and other federal officials to disclose most gifts, ethics law experts said. He also should have disclosed his trips on the yacht, these experts said.

A Supreme Court spokesperson didn’t immediately respond to a request for comment regarding the lawmakers’ calls for investigations.

Thomas has not responded to ProPublica’s questions about his travel. Crow told ProPublica that Thomas “never asked for any of this hospitality” and that his treatment of the justice was “no different from the hospitality we have extended to our many other dear friends.”

Crow said he has never discussed a pending case with Thomas. “We have never sought to influence Justice Thomas on any legal or political issue,” he said.

While justices are required by law to disclose most gifts, there are few rules on what gifts justices can accept. That’s in contrast to the other branches of government. Members of Congress are generally prohibited from taking gifts worth $50 or more and would need pre-approval from an ethics committee to take many of the trips Thomas has accepted from Crow.

On Thursday, a growing chorus of Democratic lawmakers said Thomas’ failure to disclose the luxury vacations is an example of why public trust in the Supreme Court is faltering.

Maryland Sen. Chris Van Hollen said in a statement that Americans’ confidence in the Supreme Court is “tanking because of this kind of conduct.”

“We need answers,” he said. “And the Court needs a code of ethics.”

Rhode Island Sen. Sheldon Whitehouse said in a statement that the Supreme Court has lost its ethical compass, calling for Chief Justice John Roberts to open an investigation. “It’s no wonder that the American people are losing faith in the idea that they can get a fair shake before the nation’s highest court when they see a Supreme Court justice openly flouting basic disclosure rules in order to pal around with billionaires in secret,” he said.

This year, Whitehouse and others introduced a bill that would strengthen the Supreme Court’s disclosure and recusal rules, among other reforms. In his statement, the senator called for a hearing and vote on the bill.

“The Supreme Court urgently needs an enforceable system for holding justices accountable,” he said.

Massachusetts Sen. Elizabeth Warren said Americans deserve a judiciary that is “accountable to the rule of law, not wealthy Republican donors.” ProPublica’s reporting, she added, “is a stark reminder that judges should be held to the highest ethical standards and free from conflicts of interest.”

So far, no current GOP lawmakers have addressed the revelations publicly. Sen. Lindsey Graham, ranking member for Republicans on the Senate Judiciary Committee, did not immediately respond to requests for comment. Neither did the Republican-led House Judiciary Committee.

At least two Democratic representatives have called for Thomas to be impeached or resign.

“Justice Thomas must resign immediately,” said Georgia Rep. Hank Johnson, a member of the House Judiciary Committee. Failing that, Johnson said, fellow justices should censure Thomas and the Department of Justice should investigate potential federal crimes “to determine whether Justice Thomas remains fit to retain his license to practice law.”

New York Rep. Alexandria Ocasio-Cortez said on Twitter: “This is beyond party or partisanship. This degree of corruption is shocking — almost cartoonish. Thomas must be impeached.”

Do you have any tips on the courts? Josh Kaplan can be reached by email at [email protected] and by Signal or WhatsApp at 734-834-9383. Justin Elliott can be reached by email at [email protected] or by Signal or WhatsApp at 774-826-6240.

Brett Murphy contributed reporting.